How is LED lens injection molding and in the process of injection molding attention to the problem

Today, LED series lens is widely used in lighting, indoor, outdoor, display screen, street lamp lighting project, is the key project of new energy saving in the 21st century. So, what are the problems of LED series lenses in injection molding? And what are the parameters of injection molding?

 

I, raw materials: PMMA transparent particles.

PMMA baking material temperature 75 degrees for 2H to 4H, the lens is required to be full of raw materials, can not add water, otherwise the product will change color, whitening, affect the light effect.

 

II, forming conditions:

1, molding temperature: nozzle 230 degrees, a second section of the third section of 240 to 230 degrees, plus or minus 2 degrees, 215 degrees at the end.

2. The hot runner temperature is 250 degrees, and the heat flow is divided into the runner plate, the machine nozzle, and the hot nozzle. During production, we must first check whether there is temperature at each hot nozzle.

 

Note: 1. When shooting glue, the back mold is blocked by something, mainly to prevent the temperature of the temperature control box from being too high to decompose, and to cause mold damage when driving into the mold.

2, is to prevent some hot mouth temperature low cold glue

 

III, mold temperature:

Mold temperature before and after the mold temperature, mold temperature between 80 and 90 degrees.

 

IV, pressure and speed position:

High pressure is used for pressure, and the speed is generally low speed, that is to say, the method of multi-stage injection with high pressure and low speed is mainly to prevent cold glue and flow marks.

 

VI, back pressure:

The material storage back pressure is about 2-4 mpa, and the material storage speed is 200rpm. Loose back 5 mm

VII. Time:

Injection time: 25s (seconds), injection is slow because of high pressure and low speed. If the time is too short, it will shrink and so on. Pressure holding time: 15s (seconds), cooling time: 0.

 

VIII, pressure maintenance:

Holding pressure 80-100mpa speed 100mm/s holding pressure time 15s - 20s, mainly to ensure cold shrinkage.

Major issues:

1. The lens is a high-gloss mirror. Oil stains in the production mold can not be wiped with paper or cloth, but gently wiped with medical cotton and alcohol.

2, the manipulator suction must be on the right to ensure the leveling in the laser cutting fixture, otherwise it will affect the laser cutting nozzle has to cut too high or too little.

3, laser cutting every day maintenance, ensure that the laser machine water enough, note: water can not add tap water or bottled water, must have pure mineral water, otherwise it will affect the laser cutting port cutting uneven force.

Detect light efficiency every two hours, deal with any problem in time.

5. Treatment scheme for poor appearance.

 

Common adverse analysis:

(1) bubbles

This is a cavity that occurs where the product wall is thick. Bubbles may occur outside the center of the wall thickness due to inadequate drying or excessive barrel temperature. The shrinkage phenomenon concentrated in the wall thickness will form bubbles in the central part of the wall thickness.

Countermeasures:

1, improve the mold temperature

2, lengthen the injection time

3. Add high pressure and fire in with low speed.

(2) Welding marks of products

This is due to a slight dent in the surface of the product due to the rebonding of the separated resin in the feeding hole. It is difficult to remove the joint completely depending on forming conditions.

Countermeasures:

1. Increase the temperature of the barrel
2. The lower the pressure and holding pressure, the more obvious the weld marks and the lower the strength. Increase injection pressure and speed of the end.

3, improve the mold temperature

4, increase the gate (feed mouth)

(3) uneven light effect

1, improve the temperature of the barrel to improve the mold temperature

2, improve the injection speed

3. Adjust injection pressure

(4) Product warping

Because the mold shape is different, some products after demoulding will inevitably warpage phenomenon.

 

Countermeasures:

 

1. Make a temperature difference between the rear mold and the front mold. Increase the mold temperature at which the product protrudes after demoulding.

2, reduce the mold temperature

3. Prolong the cooling time in the mold
4. Slow down the demoulding speed.

 

Dongguan Xiangshun Optics Co., Ltd. focus on optical lens product design, research and development, focus on optical lens production process continuous improvement, and material continuous optimization, product performance is widely recognized by the industry. With the gradual increase of customers' requirements for light quality, Dongguan Xiangshun Optical Technology Co., Ltd. has the responsibility to improve the product's light color and light effect to a higher height.